Canned motor device capable of detecting leakage

ABSTRACT

A canned motor device includes a motor unit and a sensor. The motor unit includes a rotor, a stator, and first and second casing bodies. The first casing body includes a first surrounding wall and a first side wall cooperating with the first surrounding wall to define an accommodating space for accommodating the rotor therein. The second casing body includes a second surrounding wall surrounding the first surrounding wall and a second side wall corresponding in position to the first side wall. The stator surrounds the second surrounding wall. The sensor is mounted to the second casing body and detects a leakage according to a change in electrostatic capacity between the first and second side walls.

FIELD

The disclosure relates to a motor device, and more particularly to acanned motor device capable of detecting leakage.

BACKGROUND

Referring to FIG. 1, a conventional magnetically driven canned motordevice disclosed in Taiwanese Patent No. 1424661 includes a front cover96, a support frame 97, an impeller 95, a cup-shaped rear cover 93, aninner rotor 92, an outer rotor 94, a fixed shaft 91 and a bracket 98.The front cover 96 has an inlet 961 and an outlet 962. The rear cover 93is a double-layered structure, and has an inner lining 931 made of afluoroplastic material and a reinforcing layer 932.

During operation of the conventional magnetically driven pump, achemical fluid is introduced into the inlet 961 and guided by theimpeller 95 to dissipate heat generated by the inner rotor 92 and thenflows out of the outlet 962. The arrows shown in FIG. 5 indicate thedirections that the chemical fluid flows.

While the inner lining 931 and the reinforcing layer 932 abut againsteach other to form the double-layered structure of the rear cover 93,the diameter of the reinforcing layer 932 is smaller than that of theinner lining 931. As such, if the inner lining 931 is damaged, chemicalfluid may easily leak through the crack of the inner lining 931 into agap between the inner lining 931 and the reinforcing layer 932, and thenflow toward the outer rotor 94 through a periphery of the reinforcedlayer 932, thereby corroding the motor device.

SUMMARY

Therefore, an object of the disclosure is to provide a canned motordevice that can alleviate the drawback of the prior art.

According to the disclosure, the canned motor device includes a baseunit, a motor unit and a leak detection sensor. The base unit includes afixed seat surrounding an axis. The motor unit includes a rotor, a firstcasing body, a second casing body and a stator. The rotor surrounds andis rotatable about the axis. The first casing body is sleeved on therotor, and includes a first surrounding wall, a first side wall, and afirst flange wall. The first surrounding wall has two ends opposite toeach other along the axis. The first side wall is connected to one ofthe ends of the first surrounding wall and cooperates with the firstsurrounding wall to define an accommodating space open at the other oneof the ends of the first surrounding wall for accommodating the rotortherein. The first flange wall is connected to the other one of the endsof the first surrounding wall and extends radially and outwardly fromthe first surrounding wall.

The second casing body is sleeved on the first casing body, and includesa second surrounding wall, a second side wall, and a second flange wall.The second surrounding wall has two ends opposite to each other alongthe axis and surrounds the first surrounding wall. The second side wallis connected to one of the ends of the second surrounding wall andcorresponds in position to the first side wall. The second flange wallis connected to the other one of the ends of the second surrounding walland extends radially and outwardly from the second surrounding wall. Thestator surrounds the second surrounding wall and corresponds in positionto the rotor. The leak detection sensor is mounted to the second casingbody and includes a sensor module configured to detect a leakageaccording to a change in electrostatic capacity between the second sidewall and the first side wall.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the disclosure will become apparent inthe following detailed description of the embodiments with reference tothe accompanying drawings, of which:

FIG. 1 is a schematic sectional view of a conventional magneticallydriven canned motor device, illustrating a chemical fluid circulating inthe conventional canned motor device;

FIG. 2 is a perspective view of a first embodiment of a canned motordevice according to the disclosure;

FIG. 3 is a sectional view of the first embodiment;

FIG. 4 is a fragmentary sectional view of the first embodiment;

FIG. 5 is a schematic sectional view of a second embodiment of thecanned motor device according to the disclosure; and

FIG. 6 is a fragmentary sectional view of the second embodiment.

DETAILED DESCRIPTION

Before the present disclosure is described in greater detail, it shouldbe noted herein that like elements are denoted by the same referencenumerals throughout the disclosure.

Referring to FIGS. 2 to 4, a first embodiment of a canned motor deviceaccording to the disclosure includes a base unit 2, a motor unit 3, anda leak detection sensor 4. The base unit 2 includes a base seat 21, afixed seat 22 surrounding an axis (L), and an annular cover 23. The baseseat 21 is mounted with the fixed seat 22. The annular cover 23 coversthe fixed seat 22. The motor unit 3 includes a rotor 31, a first casingbody 32, a second casing body 33, a stator 34 and a motor sealing ring35.

The rotor 31 surrounds and is rotatable about the axis (L). The firstcasing body 32 is sleeved on the rotor 31, and includes a firstsurrounding wall 321, a first side wall 322, a first flange wall 323,and an annular groove 324. The first surrounding wall 321 has two endsopposite to each other along the axis (L). The first side wall 322 isconnected to one of the ends of the first surrounding wall 321 andcooperates with the first surrounding wall 321 to define anaccommodating space 325 open at the other one of the ends of the firstsurrounding wall 321 for accommodating the rotor 31 therein. The firstflange wall 323 is connected to the other one of the ends of the firstsurrounding wall 321 and extends radially and outwardly from the firstsurrounding wall 321. The annular groove 324 is formed in the firstflange wall 323, and surrounds the axis (L).

The second casing body 33 is sleeved on the first casing body 32,includes a second surrounding wall 331 a second side wall 332, a secondflange wall 333, and a mounting tube 334. The second surrounding wall331 has two ends opposite to each other along the axis (L) and surroundsthe first surrounding wall 321. The second side wall 332 is connected toone of the ends of the second surrounding wall 331 and corresponds inposition to the first side wall 322. The second flange wall 333 isconnected to the other one of the ends of the second surrounding wall331 and extends radially and outwardly from the second surrounding wall331. The mounting tube 334 extends from the second side wall 332 awayfrom the first side wall 322, defines amounting space 335 for mountingof the leak detection sensor 4, and is formed with an internal thread336. The stator surrounds the second surrounding wall 331 andcorresponds in position to the rotor 31.

The leak detection sensor 4 is mounted to the mounting tube 334 of thesecond casing body 33 and includes a sensor module 41 and a shellportion 42. The sensor module 41 is configured to detect a leakageaccording to a change in electrostatic capacity between the second sidewall 332 and the first side wall 322. The shell portion 42 is mountedinto the mounting space 335 and is formed with an external thread 421engaging the internal thread 336. In this embodiment, the sensor module41 is a capacitive proximity sensor that can be short-circuited oropen-circuited when detecting a certain level of electrostatic capacity.

The motor sealing ring 35 is mounted between the first flange wall 323and the second flange wall 333. Specifically, the motor sealing ring 35is received in the annular groove 324 formed in the first flange wall323 to form an airtight seal between the first flange wall 323 and thesecond flange wall 333. In this embodiment, the motor sealing ring 35 isan O-ring.

Generally, a chemical fluid is introduced into the accommodating space325 for dissipating heat generated by the rotor 31. However, when thefirst casing body 32 is damaged or broken, the chemical fluid leaks outof the accommodating space 325 and damages the stator 34 of the motorunit 3.

The sensor module 41 continuously detects a leakage according to achange in electrostatic capacity between the second side wall 332 andthe first side wall 322. In the case that the first casing body 32 isdamaged, the chemical fluid leaking out of the accommodating space 325would flow into a space between the first side wall 322 and the secondside wall 332. Thus, the electrostatic capacity detected by the sensormodule 41 is changed. At this time, in one embodiment, an alert device(not shown) connected to the sensor module 41 outputs an alert signalsuch as light, sound, etc. to notify the user that the first casing body32 is damaged. In other embodiments, the motor unit 3 is shut down oncethe sensor module 41 detects change of electrostatic capacity. By thisway, damage to the stator 34 of the motor unit 3 can be prevented and asevere safety problem can also be avoided.

Referring to FIGS. 5 and 6, a second embodiment of the canned motordevice according to the disclosure is similar to the first embodimentand the difference between the first and the second embodiment residesin the following. In the second embodiment, the second casing body 33has a through hole 337 formed through the second side wall 332 and inspatial communication with the mounting space 335 defined by themounting tube 334. The canned motor device of the second embodimentfurther includes a sealing unit 5 including a first sealing ring 51 anda second sealing ring 52.

The first sealing ring 51 abuts against the second side wall 332 and oneend of the shell portion 42 of the leak detection sensor 4 that extendsinto the mounting space 335, and is disposed around the through hole 337to form an airtight seal between the second casing body 33 and the shellportion 42. In the case that the first casing body 32 is damaged, thechemical fluid leaking out of the accommodating space 325 flows into aspace between the first and second side walls 322, 332 and through thethrough hole 337 to contact the sensor module 41. Then, the sensormodule 41 detects a leakage according to a change in the electrostaticcapacity for subsequent procedures. The first sealing ring 51 serves asthe first line of defense to prevent the chemical fluid from leaking outof the second casing body 33 and thus preventing damage to the stator34.

Additionally, in the second embodiment, the base unit 2 further includesa lid member 24 disposed adjacent to the first and second side walls322, 332 and covering the second side wall 332 and the second mountingtube 334. The shell portion 42 of the leak detection sensor 4 includes anon-threaded mounting surface 422 which is connected to an end of theexternal thread 421 distal from the second side wall 332, which definesan annular groove, and on which the second sealing ring 52 is sleeved.The second sealing ring 52 is sleeved on the non-threaded mountingsurface 422 and abuts against the mounting tube 334 and the lid member24, so as to form an airtight seal among the mounting tube 334, the lidmember 24, and the shell portion 42. The second sealing ring 52 servesas a second line of defense to prevent the chemical fluid from leakingout of the accommodating space 325. In this embodiment, the first andsecond sealing rings 51, 52 are both O-rings. In this way, the secondembodiment possesses the advantage of the first embodiment.

To sum up, by virtue of the present disclosure, in the case that thefirst casing body 32 is damaged or broken and the chemical fluid flowsout of the accommodating space 325, the leak detection sensor 4 iscapable of detecting leakage of the chemical fluid to thereby preventdamage to the stator 34 of the motor unit 3.

In the description above, for the purposes of explanation, numerousspecific details have been set forth in order to provide a thoroughunderstanding of the embodiment. It will be apparent, however, to oneskilled in the art, that one or more other embodiments maybe practicedwithout some of these specific details. It should also be appreciatedthat reference throughout this specification to “one embodiment,” “anembodiment,” an embodiment with an indication of an ordinal number andso forth means that a particular feature, structure, or characteristicmay be included in the practice of the disclosure. It should be furtherappreciated that in the description, various features are sometimesgrouped together in a single embodiment, figure, or description thereoffor the purpose of streamlining the disclosure and aiding in theunderstanding of various inventive aspects, and that one or morefeatures or specific details from one embodiment may be practicedtogether with one or more features or specific details from anotherembodiment, where appropriate, in the practice of the disclosure.

While the disclosure has been described in connection with what isconsidered the exemplary embodiments, it is understood that thisdisclosure is not limited to the disclosed embodiments but is intendedto cover various arrangements included within the spirit and scope ofthe broadest interpretation so as to encompass all such modificationsand equivalent arrangements.

What is claimed is:
 1. A canned motor device comprising: a base unitincluding a fixed seat surrounding an axis; a motor unit including arotor surrounding and rotatable about the axis, a first casing bodysleeved on said rotor, and including a first surrounding wall that hastwo ends opposite to each other along the axis, a first side wall thatis connected to one of said ends of said first surrounding wall and thatcooperates with said first surrounding wall to define an accommodatingspace open at the other one of said ends of said first surrounding wallfor accommodating said rotor therein, and a first flange wall that isconnected to said other one of said ends of said first surrounding walland that extends radially and outwardly from said first surroundingwall, a second casing body sleeved on said first casing body, includinga second surrounding wall that has two ends opposite to each other alongthe axis and that surrounds said first surrounding wall, a second sidewall that is connected to one of said ends of said second surroundingwall and that corresponds in position to said first side wall, and asecond flange wall that is connected to the other one of said ends ofsaid second surrounding wall and that extends radially and outwardlyfrom said second surrounding wall, and a stator surrounding said secondsurrounding wall and corresponding in position to said rotor; and a leakdetection sensor mounted to said second casing body and including asensor module configured to detect a leakage according to a change inelectrostatic capacity between said second side wall and said first sidewall.
 2. The canned motor device as claimed in claim 1, wherein saidsecond casing body includes a mounting tube extending from said secondside wall away from said first side wall and defining a mounting spacefor mounting of said leak detection sensor.
 3. The canned motor deviceas claimed in claim 2, wherein said mounting tube is formed with aninternal thread, said leak detection sensor further including a shellportion mounted into said mounting space and formed with an externalthread engaging said internal thread.
 4. The canned motor device asclaimed in claim 3, wherein said second casing body has a through holeformed through said second side wall and in spatial communication withsaid mounting space defined by said mounting tube.
 5. The canned motordevice as claimed in claim 4, further comprising a sealing unitincluding a first sealing ring abutting against said second side walland one end of said shell portion that extends into said mounting space,and disposed around said through hole to form an airtight seal betweensaid second casing body and said shell portion.
 6. The canned motordevice as claimed in claim 5, wherein said base unit further includes alid member covering said second side wall and the mounting tube, saidsealing unit further including a second sealing ring sleeved on saidshell portion and abutting against said mounting tube and said lidmember, so as to form an airtight seal among said mounting tube, saidpressing member, and said shell portion.
 7. The canned motor device asclaimed in claim 6, wherein said shell portion includes a non-threadedmounting surface which is connected to an end of said external threaddistal from said second side wall, which defines an annular groove, andon which said second sealing ring is sleeved.
 8. The canned motor deviceas claimed in claim 1, wherein said motor unit further includes a motorsealing ring mounted between said first flange wall and said secondflange wall, said first casing body having an annular groove formed insaid first flange wall, surrounding said axis, and receiving said motorsealing ring to form an airtight seal between said first flange wall andsaid second flange wall.
 9. The canned motor device as claimed in claim1, wherein said base unit further includes a base seat mounted with saidfixed seat, and an annular cover covering said fixed seat.